This grave marks the passing of a historic Jane Doe whose identity remains a mystery to this day.

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

An Industrial Revolution-era public work that purified water using nothing but sand.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

People escaping slavery may have hidden inside a corpse vault.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

This grand gothic brewery has been pumping out suds for over a hundred years.

Teeming with illegal goods and services, this towering maze of vice is also a popular tourist accommodation.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

The burial grounds of a secret society includes fences topped with fake Tesla balls.

Colorado's only true geyser is hidden within the San Juan National Forest.

The remains of an early 1900s dude ranch that operated until the 1970s.

The oldest operating cemetery in Denver is the eternal home of some of the Centennial State's most famous residents.

This grand stone tower was dedicated to a famed American humorist almost by coincidence.

Travel through the wholesome amusements of yesteryear at this charming miniature village.

Even in death, he's still your huckleberry.

This tea house was a hand-built gift from Boulder's sister city in Tajikstan.

At the tallest peak in Colorado, an electrifying mix of thin air, lightning, and rivalry.

One woman's UFO-themed campground, complete with self-built energy vortexes, UFO-themed weddings, and magic bushes.

These faux-cliff dwellings allow visitors to climb around on a replica archaeological site.

Abandoned silver mine strewn with wrecked and twisted structures.